After entering summer, the temperature is getting higher and higher, and people are sweating when they go out. In order to be cool, people’s clothes are getting less and less. Many men have changed to wear vests or even bare arms; Women also wear suspenders, shorts and miniskirts to cool down. In other words, is it true that the less you wear, the cooler you will be?
Passerby A: “of course, it’s not cool to wear nothing.”
Passerby B: “why do Arabs in the desert wear robes all year round?”
From a scientific point of view, it is not really cool to wear less. When the temperature is higher than 33 degrees, it is hot to wear less!
the cooler you wear less in summer? Or will it be hotter
the less you wear, the hotter it gets
As we all know, the skin covering the surface of the human body has many functions such as protection, sensation, temperature regulation, secretion, excretion, metabolism and so on. There are millions of pores in our human skin, which need to discharge a lot of sweat every day, and the evaporation of sweat can take away heat. According to statistics, 246 joules of heat are taken away by evaporation of every milliliter of sweat on the skin surface.
Under normal circumstances, under the regulation of nerves and body fluids, the human body temperature is constant, about 37 ℃. Research shows that when the ambient temperature is between 18 ℃ and 28 ℃, about 70% of human body temperature is dissipated through skin radiation, convection and conduction.
As the temperature rises, sweating increases, mainly through sweat evaporation and heat dissipation, so that the body temperature is not too high. Especially when the ambient temperature is close to the skin temperature of the human body, the heat dissipation of the human body is almost completed by sweating.
When the ambient temperature is higher than the skin temperature, it is not only impossible to dissipate heat by radiation, but also the human body will absorb heat from the external environment. At this time, if you are bare, the skin will start to absorb heat from the outside.
In addition, in high-temperature weather, sweat is constantly secreted from pores, and small sweat drops slowly converge into larger sweat drops. Large sweat drops are easily lost quickly, which can not play the role of evaporation and heat dissipation. In this way, the skin will not only absorb external heat, but also cannot dissipate heat by evaporating sweat. How can it be cool? My body will not be comfortable. Moreover, it is easy to suffer from solar dermatitis if you bare your arms in the hot sun for a long time.
If the temperature is lower than the body temperature, or when there is wind outside, it is cooler to wear bare arms than to wear clothes.
what clothes are cooler
If you want to feel cool in summer, you should pay attention to the selection of clothes. Choose some breathable cotton silk woven clothes, so that there is a thin air layer between the clothes and the skin, and the temperature of the air layer is always lower than the outside temperature, so as to achieve the effect of heatstroke prevention and cooling, and make people feel cool.
According to the measurement, when the temperature is 24 ℃ and the relative humidity is about 60%, the moisture absorption rate of silk is about 10%, that of cotton is about 8%, and that of synthetic fiber is the worst, less than 3%. Therefore, if you want to wear comfortable and cool clothes, you’d better wear some silk clothes and cotton clothes of plant fiber in summer. Of course, you should also consider the “wind absorption” and “wind blowing” effects of clothes. Clothes should be loose, especially the openings of collar, sleeve and trouser leg. For example, jumpsuits and flared skirts will be cooler to wear. Jeans and tights are not suitable for summer.
Leave a Reply